Busbar and battery module

Abstract

The positive electrode bus bar (300) includes a fuse portion (312) extending in a prescribed direction, and an insulating material (320) that surrounds substantially the central portion of the fuse portion (312) in the prescribed direction, without surrounding both end portions of the fuse portion (312) in the prescribed direction.

Description

Technical Field

[0001] This invention relates to a busbar and a battery module. Background Technology

[0002] In recent years, various battery modules have been developed. A battery module includes battery cells and busbars that are electrically connected to the battery cells.

[0003] The busbar is described in Patent Document 1. The busbar includes a fusible portion and a fireproof sleeve covering the fusible portion.

[0004] Patent document 2 describes a busbar plate. The busbar plate includes a fuse section and an insulating member surrounding the outer surface of the fuse section.

[0005] The busbar is described in Patent Document 3. The busbar includes a curved fuse protrusion and an insulating member surrounding the curved fuse protrusion.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Chinese Utility Model No. 219717185

[0009] Patent Document 2: Japanese Patent Publication No. 2022-534951

[0010] Patent Document 3: U.S. Patent Application Publication No. 2014 / 0315051 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] As described in Patent Document 1, from the viewpoint of thermal insulation, the fuse wire of a busbar is sometimes surrounded by a surrounding material such as a fireproof sleeve. However, when the fuse wire is surrounded by a surrounding material, the duration of the arc discharge that accompanies the melting of the fuse wire can sometimes be longer. The longer the arc discharge time, the more likely the area of ​​the busbar to be melted is to expand. The larger the area of ​​the busbar to be melted, the more difficult it is sometimes to suppress damage to components present around the fuse wire.

[0013] One example of the object of the present invention is to rapidly suppress arc discharge that accompanies the melting of a fuse. Other objects of the present invention will become apparent from the description herein.

[0014] Technical means to solve the problem

[0015] An embodiment of the present invention is described below.

[0016] 1. A busbar, comprising:

[0017] The fuse extends in a specified direction; and

[0018] The material surrounds the approximately central portion of the fuse in the specified direction, without enclosing the two ends of the fuse in the specified direction.

[0019] 2. The busbar according to 1, wherein the surrounding material is an insulating material.

[0020] 3. The busbar according to 1 or 2, wherein the surrounding material contains at least one of glass fiber, ceramic and Si compound.

[0021] 4. The busbar according to any one of 1 to 3, wherein the surrounding material is configured to substantially maintain the shape of the surrounding material from the moment the fuse melts until the end of the arc discharge that accompanies the melting of the fuse.

[0022] 5. The busbar according to any one of 1 to 4, wherein the dimension of the surrounding material in the specified direction is smaller than the dimension of the fuse in the specified direction.

[0023] 6. The busbar according to any one of 1 to 5, wherein the dimension of the surrounding material in the specified direction is more than 50% of the dimension of the fuse in the specified direction.

[0024] 7. The busbar according to any one of 1 to 6, wherein the time of the arc discharge resulting from the melting of the fuse is less than 13 milliseconds.

[0025] 8. A battery module, comprising:

[0026] Battery cells; and

[0027] The busbar according to any one of 1 to 7 is electrically connected to the battery cell.

[0028] The effects of the invention

[0029] Through the embodiments described in this invention, arc discharge that accompanies the melting of the fuse can be rapidly suppressed. Attached Figure Description

[0030] [ Figure 1 [ ] is a perspective view of the battery module in the implementation method.

[0031] [ Figure 2 [Illustration] is a perspective view of a portion of the positive busbar in the embodiment.

[0032] [ Figure 3 ]yes Figure 2 AA section.

[0033] [ Figure 4 [Illustration 1] is a circuit model showing the arc discharge of the fuse portion of the positive busbar in an embodiment.

[0034] [ Figure 5 [Illustration] is a diagram used to illustrate the arc discharge generated when the fuse portion of the accompanying embodiment melts.

[0035] [ Figure 6 [Illustration] is a diagram used to illustrate the arc discharge generated when the fuse portion of the accompanying embodiment melts.

[0036] [ Figure 7 [Illustration] is a diagram used to illustrate the arc discharge generated when the fuse portion of the accompanying embodiment melts.

[0037] [ Figure 8 [This is a graph showing the time shift of the current when the fuse portion of the busbar in Example 1 is melted.]

[0038] [ Figure 9 [This is a graph showing the time shift of the current when the fuse portion of the busbar in Example 2 is melted.]

[0039] [ Figure 10 [This is a graph showing the time shift of the current when the fuse portion of the busbar in the comparative example is melted.] Detailed Implementation

[0040] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. In all the drawings, the same reference numerals are used to denote the same components, and descriptions are appropriately omitted.

[0041] Figure 1 This is a perspective view of battery module 1 according to the implementation method.

[0042] exist Figure 1For illustrative purposes, arrows representing the X, Y, and Z directions are shown. Unless otherwise specified, the tip of the arrow representing the X direction will be considered the rear side of battery module 1, and the base of the arrow representing the X direction will be considered the front side of battery module 1. The Y direction is orthogonal to the X direction. The Y direction is the left-right direction of battery module 1. Unless otherwise specified, the tip of the arrow representing the Y direction will be considered the left side of battery module 1, and the base of the arrow representing the Y direction will be considered the right side of battery module 1. The Z direction is orthogonal to both the X and Y directions. The Z direction is the up-down direction of battery module 1. Unless otherwise specified, the tip of the arrow representing the Z direction will be considered the top side of battery module 1, and the base of the arrow representing the Z direction will be considered the bottom side of battery module 1. Unless otherwise specified, the +X side and -X side refer to the tip and base of the arrow representing the X direction, respectively; the +Y side and -Y side refer to the tip and base of the arrow representing the Y direction, respectively; and the +Z side and -Z side refer to the tip and base of the arrow representing the Z direction, respectively. Furthermore, the relationship between the X, Y, and Z directions and the front-back, left-right, and up-down directions of the battery module 1 is not limited to the examples described.

[0043] Reference Figure 1 The structure of battery module 1 will be described.

[0044] The battery module 1 includes a cell stack 10 and a voltage detection device 20. The cell stack 10 has multiple battery cells 100. The voltage detection device 20 detects the voltage of the multiple battery cells 100. The voltage detection device 20 has a holding body 200, multiple voltage detection terminals 210, a positive bus bar 300, and a negative bus bar 400.

[0045] Multiple battery cells 100 are stacked in the Y direction. The length direction of each battery cell 100 is approximately parallel to the X direction. The width direction of each battery cell 100 is approximately parallel to the Z direction. The thickness direction of each battery cell 100 is approximately parallel to the Y direction. The shape of each battery cell 100 is not limited to this example.

[0046] Each battery cell 100 includes a battery component (not shown), an outer casing 102, a positive electrode tab 104, and a negative electrode tab 106. In one example, the battery component includes a plurality of positive and negative electrodes (not shown) alternately stacked in the Y direction, and a separator (not shown) located between adjacent positive and negative electrodes in the Y direction. The outer casing 102 seals the battery component with an electrolyte (not shown). The positive electrode tab 104 is electrically connected to the positive electrode of the battery component. The positive electrode tab 104 is led out from one of the two sides of the outer casing 102 in the X direction. The negative electrode tab 106 is electrically connected to the negative electrode of the battery component. The negative electrode tab 106 is led out from the other side of the outer casing 102 in the X direction. However, the structure of each battery cell 100 is not limited to this example.

[0047] Each battery cell 100 may also be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in the portion that corresponds to the separator. All-solid-state batteries do not contain electrolyte. Hereinafter, unless otherwise specified, each battery cell 100 will be described as a battery cell containing electrolyte.

[0048] In this embodiment, multiple battery cells 100 are electrically connected by a combination of series and parallel connections. Specifically, a cell group comprising at least two adjacent and parallel-connected battery cells 100 in the Y direction is stacked and connected in series in the Y direction. On the -X side of the cell stack 10, a positive electrode tab 104 derived from the battery cells 100 of the parallel-connected cell group is electrically connected to a negative electrode tab 106 derived from the battery cells 100 of another parallel-connected cell group, thereby forming a tab connection portion 108 comprising the positive electrode tab 104 and the negative electrode tab 106. The positive electrode tab 104 and the negative electrode tab 106 in the tab connection portion 108 are joined together, for example, by laser welding. A tab group is also formed on the +X side of the cell stack 10 in the same way. Therefore, multiple cell groups are connected in series from the cell group at one end of the cell stack 10 in the Y direction to the cell group at the other end of the cell stack 10 in the Y direction.

[0049] The electrical connection of the multiple battery cells 100 is not limited to the example described. For example, individual battery cells 100 may also be connected in series to form a cell stack 10.

[0050] The retainer 200 is disposed on the -X side relative to the unit stack 10. The retainer 200 defines a plurality of openings 202. Each of the plurality of tab connections 108 is exposed toward the -X side via each of the plurality of openings 202. The retainer 200 integrally holds a plurality of voltage detection terminals 210. Therefore, by positioning the retainer 200 relative to the unit stack 10, each of the plurality of voltage detection terminals 210 can be positioned relative to each of the plurality of tab connections 108.

[0051] The +X side of each voltage detection terminal 210 and the -X side of each tab connection 108 are joined together, for example, by a joining method such as laser welding. Therefore, each voltage detection terminal 210 and each tab connection 108 are electrically connected to each other. Thus, the voltage detection device 20 can detect the voltage of each tab connection 108 through each voltage detection terminal 210. Each voltage detection terminal 210 is electrically connected to a connector (not shown) via a voltage detection line such as a wire harness (not shown).

[0052] A positive busbar 300 is disposed at the -Y side end of the retainer 200. The positive busbar 300 is electrically connected to a positive electrode tab 104 extending from the unit group at the -Y side end of the unit stack 10. The positive busbar 300 functions as an external terminal for electrical connection to other external devices such as battery modules. A negative busbar 400 is disposed at the +Y side end of the retainer 200. The negative busbar 400 is electrically connected to a negative electrode tab 106 extending from the unit group at the +Y side end of the unit stack 10. The negative busbar 400 functions as an external terminal for electrical connection to other external devices such as battery modules.

[0053] On the +X side of the unit stack 10, except that the positive busbar 300 and the negative busbar 400 are not provided, a voltage detection device identical to the voltage detection device 20 is provided. Therefore, the voltage of the multiple tab connections on the +X side of the unit stack 10 can be detected.

[0054] In this embodiment, the positive electrode tab 104 of the terminals of the series-connected multiple unit groups extends from the battery cell 100 of the unit group located on the -Y side of the unit stack 10 toward the -X side, and the negative electrode tab 106 of the terminals of the series-connected multiple unit groups extends from the battery cell 100 of the unit group located on the +Y side of the unit stack 10 toward the -X side. Therefore, both the positive busbar 300 and the negative busbar 400 are disposed on the -X side of the battery cell 100. However, the configuration of the positive electrode tab 104 and the negative electrode tab 106 of the terminals of the series-connected multiple unit groups sometimes varies depending on the number of battery cells 100 included in the unit stack 10. For example, consider the following scenario: the positive electrode tab 104 of the terminal of multiple unit groups connected in series extends from the battery cell 100 of the unit group located on the -Y side of the unit stack 10 toward the +X side; the negative electrode tab 106 of the terminal of multiple unit groups connected in series extends from the battery cell 100 of the unit group located on the +Y side of the unit stack 10 toward the -X side. In this case, the positive electrode busbar 300 is disposed on the +X side of the unit stack 10, and the negative electrode busbar 400 is disposed on the -X side of the unit stack 10.

[0055] Figure 2 This is a perspective view of a portion of the positive busbar 300 in the embodiment. Figure 3 yes Figure 2 Section AA. (Refer to...) Figure 2 and Figure 3 The same points that apply to the positive busbar 300 and the negative busbar 400 have a generally symmetrical shape can also be applied to the negative busbar 400.

[0056] In this embodiment, the positive busbar 300 comprises copper. However, the positive busbar 300 may also comprise a metal different from copper. Figure 2 and Figure 3 As shown, the positive busbar 300 has an extended conductor 310 and an insulating material 320.

[0057] The extension conductor 310 extends in the Y direction. The extension conductor 310 includes a fuse portion 312, a first extension portion 314, and a second extension portion 316. The fuse portion 312, the first extension portion 314, and the second extension portion 316 extend in the Y direction. The +Y side end of the fuse portion 312 and the -Y side end of the first extension portion 314 are electrically connected to each other. The -Y side end of the fuse portion 312 and the +Y side end of the second extension portion 316 are electrically connected to each other.

[0058] The fuse 312 is designed to melt in case of an overcurrent exceeding a certain value flowing through the positive busbar 300 due to factors such as an malfunction of the battery cell 100. The overcurrent that the fuse 312 can withstand varies depending on the capacity of the battery module 1, for example, approximately 6,000 A. Figure 2 In the example shown, the fuse portion 312 is defined by a cut 313 formed on the -X side of the extension conductor 310. Through the cut 313, the dimension of the fuse portion 312 in the X direction is smaller than each of the dimensions of the first extension portion 314 and the second extension portion 316 in the X direction. Therefore, the cross-sectional area of ​​the fuse portion 312 perpendicular to the Y direction is smaller than each of the cross-sectional areas of the first extension portion 314 and the second extension portion 316 perpendicular to the Y direction.

[0059] The method of making the cross-sectional area of ​​the fuse portion 312 perpendicular to the Y direction smaller than each of the cross-sectional areas of the first extension portion 314 perpendicular to the Y direction and the cross-sectional areas of the second extension portion 316 perpendicular to the Y direction is not limited to Figure 2The example shown. For example, cutout 313 may also be formed on the edge of the extension conductor 310 on the +X side. Alternatively, cutout 313 may also be formed on both sides of the extension conductor 310 in the Y direction. Alternatively, the dimension of the fuse portion 312 in the Z direction may be smaller than each of the dimensions of the first extension portion 314 in the Z direction and the dimensions of the second extension portion 316 in the Z direction.

[0060] like Figure 2 and Figure 3 As shown, the insulating material 320 is a surrounding material that surrounds the fuse portion 312 in the Y direction. Figure 2 As shown, the insulating material 320 does not surround the two ends of the fuse portion 312 in the Y direction, but rather surrounds approximately the central portion of the fuse portion 312 in the Y direction. That is, the dimension of the insulating material 320 in the Y direction is smaller than the dimension of the fuse portion 312 in the Y direction. Therefore, the two ends of the fuse portion 312 in the Y direction are exposed from the insulating material 320. In this embodiment, compared to the case where no part of the fuse portion 312 is surrounded by the insulating material 320, the thermal insulation and electrical insulation between the fuse portion 312 and its surroundings can be improved, thereby improving the reliability of the operation of the fuse portion 312.

[0061] exist Figure 3 In the example shown, the insulating material 320 is disposed around the fuse portion 312 in the Y direction. For example, the insulating material 320 is an insulating tape wound around the fuse portion 312 in the Y direction. Alternatively, the insulating material 320 may also be an insulating tube surrounding the fuse portion 312 in the Y direction. In these examples, compared to disposing of insulating blocks such as resin blocks around the fuse portion 312 in the Y direction, or coating the surface of the fuse portion 312 in the Y direction with an insulating layer such as a resin layer, it is easier to surround the fuse portion 312 in the Y direction with a surrounding material. The arrangement of the insulating material 320 is not limited to... Figure 3 The example shown. Alternatively, the surrounding material that surrounds the fuse portion 312 in the Y direction may be an insulating block such as a resin block disposed around the fuse portion 312 in the Y direction, or an insulating layer such as a resin layer coated on the surface of the fuse portion 312 in the Y direction.

[0062] The insulating material 320 has heat resistance capable of withstanding the heat generated during normal operation of the positive busbar 300. However, the insulating material 320 may not be resistant to the heat generated when the fuse portion 312 melts. For example, the insulating material 320 may not be resistant to temperatures above 1085°C, which is the melting point of the copper constituting the fuse portion 312. However, the insulating material 320 may also be fire-resistant. When the insulating material 320 is fire-resistant, the fire resistance of the fuse portion 312 can be improved. The insulating material 320 may contain, for example, at least one of glass fiber, ceramic, and a Si compound.

[0063] A retaining strip (not shown) may also be wound around the fuse portion 312 on the outer side of the fuse portion 312, further out in the Y direction than the insulating material 320. The retaining strip helps to secure the insulating material 320 to the fuse portion 312. The retaining strip also helps to prevent the insulating material 320 from shifting position on the fuse portion 312 and prevents the insulating material 320 from being detached from the fuse portion 312.

[0064] Figure 4 This is a diagram illustrating a circuit model of the arc discharge of the fuse portion 312 of the positive busbar 300 according to an embodiment. Using Figure 4 The instructions apply not only to the fuse portion 312 of the positive busbar 300, but also to the fuse portion of the negative busbar 400.

[0065] The inventors of this application conducted research and determined that if an overcurrent flows through the positive busbar 300, the fuse portion 312 may sometimes melt, subsequently causing an arc discharge between the -Y side end of the first extension portion 314 and the +Y side end of the second extension portion 316. The longer the arc discharge lasts, the more likely the area of ​​the positive busbar 300 to melt is to expand. The larger the area of ​​the positive busbar 300 melts, the more difficult it becomes to suppress damage to components surrounding the fuse portion 312, such as portions of the positive busbar 300 other than the fuse portion 312, or portions surrounding the fuse portion 312 of the retainer 200. Therefore, to suppress damage to components surrounding the fuse portion 312, it is necessary to rapidly suppress the arc discharge time.

[0066] exist Figure 4 In the model shown, V0 represents the voltage of the unit stack 10, and R0 represents the total resistance of all components constituting the circuit of the battery module 1, including the battery cell 100 and the wiring electrically connected to the battery cell 100. arc This refers to the arc voltage of the arc discharge generated between the -Y side end of the first extension 314 and the +Y side end of the second extension 316. For example... Figure 4 As shown in the model, at the length L of the arc discharge arc In the middle, the arc voltage V arc It includes the anode voltage drop, cathode voltage drop, and arc column voltage. To suppress arc discharge, the arc voltage V... arc The voltage must be above V0. According to... Figure 4 The model shown requires increasing the resistance to arc discharge in order to suppress it.

[0067] Figures 5-7 This is a diagram illustrating the arc discharge EA generated when the fuse portion 312 of the accompanying embodiment melts. Figures 5-7A schematic cross-section perpendicular to the X-direction is shown of the approximate central portion of the fuse portion 312 and the insulating material 320 in the X-direction. (Using...) Figures 5-7 The instructions apply not only to the fuse portion 312 of the positive busbar 300, but also to the fuse portion of the negative busbar 400.

[0068] First, such as Figure 5 As shown, before the fuse portion 312 melts, the insulating material 320 does not surround the two ends of the fuse portion 312 in the Y direction, but surrounds the approximate central portion of the fuse portion 312 in the Y direction.

[0069] Next, as Figure 6 As shown, if an overcurrent flows through the positive busbar 300, the fuse portion 312 melts, and an arc discharge EA is generated between the end of the first extension portion 314 on the -Y side and the end of the second extension portion 316 on the +Y side, through the space surrounded by the insulating material 320 in the Y direction.

[0070] The melting of fuse 312 generates a force that propels objects around fuse 312 away. For example... Figure 5 As shown, before the fuse portion 312 melts, the insulating material 320 does not surround the two ends of the fuse portion 312 in the Y direction, but rather surrounds approximately the central portion of the fuse portion 312 in the Y direction. Therefore, before the fuse portion 312 melts, the insulating material 320 is not supported from the two ends of the fuse portion 312 in the Y direction. Therefore, as Figure 7 As shown, due to the melting of the fuse portion 312, the insulating material 320 is ejected from the location where the fuse portion 312 exists. Figure 7 In the example shown, the insulating material 320 is bounced off the +Z side relative to the position where the fuse portion 312 exists. However, the direction in which the insulating material 320 is bounced off is not limited to... Figure 7 The direction shown varies depending on the melting condition of the fuse portion 312.

[0071] The insulating material 320 possesses durability such as strength and heat resistance: even if the insulating material 320 is ejected due to the melting of the fuse portion 312, it largely maintains the surrounding shape of the insulating material 320 as it would have with the fuse portion 312 present. Therefore, as... Figure 7 As shown, even if the insulation material 320 is thrown away due to the melting of the fuse portion 312, the insulation material 320 generally maintains its surrounding shape. Therefore, as Figure 7As shown, if the insulating material 320 is ejected, an arc discharge EA is generated between the end of the first extension 314 on the -Y side and the end of the second extension 316 on the +Y side through the space surrounded by the insulating material 320. The insulating material 320 has the following durability, such as strength and heat resistance: from the melting of the fuse portion 312 to the end of the arc discharge EA, the shape of the insulating material 320 is substantially maintained. That is, the insulating material 320 is configured to substantially maintain its shape from the melting of the fuse portion 312 to the end of the arc discharge EA.

[0072] In this embodiment, compared to the case where the insulating material 320 surrounds the entire Y-direction of the fuse portion 312 before it melts, by allowing ambient low-temperature air to flow into the space between the -Y side end of the first extension portion 314 and the +Y side end of the second extension portion 316, the insulation strength of the space can be restored, thereby increasing the resistance to arc discharge. Therefore, in this embodiment, compared to the case where the insulating material 320 surrounds the entire Y-direction of the fuse portion 312 before it melts, arc discharge can be suppressed more rapidly.

[0073] The dimension of the insulating material 320 in the Y direction is not particularly limited. In one example, from the viewpoint of facilitating the flow of ambient low-temperature air into the space between the -Y side end of the first extension 314 and the +Y side end of the second extension 316, the dimension of the insulating material 320 in the Y direction is preferably a ratio to the dimension of the fuse portion 312 in the Y direction that is less than a certain value. Alternatively, the dimension of the insulating material 320 in the Y direction may be, for example, 50% or more of the dimension of the fuse portion 312 in the Y direction. When the dimension of the insulating material 320 in the Y direction is 50% or more of the dimension of the fuse portion 312 in the Y direction, compared to the case where the dimension of the insulating material 320 in the Y direction is less than 50% of the dimension of the fuse portion 312 in the Y direction, it is... Figure 7 As shown, when the insulating material 320 is deflected, the distance from the -Y side end of the first extension 314 and the +Y side end of the second extension 316 to the first extension 314 can be shortened, making it easier to contain the arc discharge EA within the area surrounded by the insulating material 320. Therefore, compared to the case where the arc discharge EA is generated outside the area surrounded by the insulating material 320, as Figure 7As shown, when the insulating material 320 is deflected, the arc discharge EA can be easily interrupted from the -Y side end of the first extension 314 and the +Y side end of the second extension 316, thus easily shortening the time of the arc discharge EA. Furthermore, when the dimension of the insulating material 320 in the Y direction is 50% or more of the dimension of the fuse portion 312 in the Y direction, compared to when the dimension of the insulating material 320 in the Y direction is less than 50% of the dimension of the fuse portion 312 in the Y direction, the strength of the insulating material 320 can be improved, such as... Figure 7 As shown, even if the insulating material 320 is bounced away, it can easily maintain the surrounding shape of the insulating material 320.

[0074] Figure 8 This is a graph showing the time-varying current when the fuse portion of the busbar in Example 1 is melted. Figure 9 This is a graph showing the time shift of the current when the fuse portion of the busbar in Example 2 is melted. Figure 10 This is a graph showing the time-varying current when the fuse portion of the busbar in the comparative example is blown. Figures 8-10 In the chart shown, the horizontal axis represents time (in seconds) and the vertical axis represents current (in A).

[0075] The busbar of Example 1 has a fuse portion. The fuse portion extends in a predetermined extension direction. The dimension of the fuse portion in the extension direction is 20 mm. In the fuse portion, a ceramic-glass strip is wound around the extension direction of the fuse portion. The strip of Example 1 does not surround the two ends of the extension direction of the fuse portion but surrounds approximately the central portion of the extension direction of the fuse portion. That is, in the extension direction of the fuse portion, the dimension of the strip of Example 1 is smaller than the dimension of the fuse portion. The dimension of the fuse portion of the strip of Example 1 in the extension direction is 10 mm. The busbar of Example 1 corresponds to the positive busbar 300 of the embodiment. The fuse portion of Example 1 corresponds to the fuse portion 312 of the embodiment. The strip of Example 1 corresponds to the insulating material 320 of the embodiment. The extension direction of Example 1 corresponds to the Y direction of the embodiment.

[0076] The busbar of Example 2 is the same as that of Example 1, except that instead of ceramic glass tape, glass fiber tape is wound around the fuse portion in the extension direction of the fuse portion.

[0077] The comparative example busbar is identical to the busbar of Example 1, except that instead of the strip of Example 1, it uses a silicone and aluminum-coated glass fiber strip that not only surrounds the fuse portion but also surrounds the extension portions on both sides of the fuse portion in the extending direction relative to the busbar. That is, the size of the comparative example strip is larger than the size of the fuse portion in the extending direction. The dimension of the comparative example strip in the extending direction of the fuse portion is 30 mm. The extension portions of the comparative example correspond to the first extension portion 314 and the second extension portion 316 of the embodiment.

[0078] exist Figure 8 The chart shown Figure 9 The charts shown and Figure 10 In any of the graphs shown, the current decreases as the fuse partially melts around 0.15 seconds into the arc. The duration of the arc discharge can be estimated as the time from the point when the current begins to decrease due to the melting of the fuse portion to the point when the current reaches zero. Furthermore, Figure 8 The chart shown Figure 9 The charts shown and Figure 10 The current rise near 0 seconds in the graph shown indicates the start-up of the test setup.

[0079] like Figure 8 As shown, in the busbar of Example 1, the current drops to 0 almost instantaneously from the point when the fuse partially melts at approximately 0.15 seconds. Therefore, it can be said that in the busbar of Example 1, the arc discharge time is almost zero.

[0080] like Figure 9 As shown, in the busbar of Example 2, the current drops to 0 approximately 13 milliseconds from the point when the fuse portion begins to melt around 0.15 seconds. Therefore, it can be said that in the busbar of Example 2, the arc discharge time is approximately 13 milliseconds.

[0081] like Figure 10 As shown, in the comparative example busbar, the current drops to 0 approximately 116 milliseconds from the point when the fuse partially melts around 0.15 seconds. Therefore, it can be said that the arc discharge time in the comparative example busbar is approximately 116 milliseconds.

[0082] according to Figures 8-10 The results shown indicate that by having the insulating material surround approximately the central portion of the fused section's extension direction instead of the two ends of the fused section, arc discharge can be rapidly suppressed.

[0083] The embodiments of the present invention have been described above with reference to the accompanying drawings, but these are examples of the present invention, and various other structures may also be used.

[0084] This application claims priority based on Japanese Patent Application No. 2024-060116, filed on April 3, 2024, the entire contents of which are incorporated herein by reference.

[0085] Explanation of icon numbers

[0086] 1: Battery Module

[0087] 10: Unitary laminate

[0088] 20: Voltage detection device

[0089] 100: Battery cell

[0090] 102: Exterior materials

[0091] 104: Positive electrode tab

[0092] 106: Negative electrode tab

[0093] 108: Electrode Connection Part

[0094] 200: Maintain body

[0095] 202: Opening

[0096] 210: Voltage detection terminal

[0097] 300: Positive busbar

[0098] 310: Extended conductor

[0099] 312: Fuse Section

[0100] 313: Incision

[0101] 314: First Extension

[0102] 316: Second Extension

[0103] 320: Insulating material

[0104] 400: Negative busbar

Claims

1. A busbar, comprising: The fuse extends in a specified direction; as well as The material surrounds the approximately central portion of the fuse in the specified direction, without enclosing the two ends of the fuse in the specified direction.

2. The busbar according to claim 1, wherein the surrounding material is an insulating material.

3. The busbar according to claim 1, wherein the surrounding material comprises at least one of glass fiber, ceramic and Si compound.

4. The busbar according to claim 1, wherein the surrounding material is configured to substantially maintain the shape of the surrounding material from the moment the fuse melts until the end of the arc discharge that accompanies the melting of the fuse.

5. The busbar according to claim 1, wherein the dimension of the surrounding material in the specified direction is smaller than the dimension of the fuse in the specified direction.

6. The busbar according to claim 1, wherein the dimension of the surrounding material in the specified direction is more than 50% of the dimension of the fuse in the specified direction.

7. The busbar according to claim 1, wherein the arc discharge time accompanying the melting of the fuse is less than 13 milliseconds.

8. A battery module, comprising: Battery cell; as well as The busbar as described in any one of claims 1 to 7 is electrically connected to the battery cell.

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